A rare case of primary pulmonary amyloidosis with hilar lymphadenopathy is described. Immunological studies showed decreases in serum IgG and IgM levels. However, both pokeweed mitogen (PWM)-induced IgG production and proliferation of peripheral blood B cells were not disordered. The response of peripheral blood lymphocytes (PBL) to stimulation with PWM, phytohemagglutinin, or concanavalin A was found to be normal. In addition, the proportion of E and EACrosette-forming cells in PBL from this patient did not differ from that in PBL from normal donors. The positive response of skin test to recall antigens also gave an evidence that the patient had not a depression in systemic cell-mediated immunity. These findings contrast with those previously described for systemic amyloidosis in man and in animals.